Properly handle systemd presets in Lua scripts
There were several problems here:
1) At some point, arg[2] of Lua RPM scripts stopped comparing TRUE
to "1" and started returning "1.0" in string context. This patch
changes the comparison to function in numeric context instead.
2) The logic to put the preset file in place and activate its
differences was incorrectly conflated. The preset file should
always be put in place, but the presets should only be applied on
initial installation.
3) The close() on the file descriptor reading the presets happened
too early.
4) The symlink for the preset was pointing at a typoed directory name
5) Uninstallation was not properly setting the variant to "nonproduct"
Resolves: rhbz#1317721
Signed-off-by: Stephen Gallagher <sgallagh@redhat.com>